doc: add detector and template defs.

The detector def also includes auditor and reactor defs.

Template as in html template also provides context/def for tracker template.

Author: rouilj

doc/glossary.txt

@@ -32,6 +32,20 @@ Roundup Glossary
       a dash '-', and a number. E.g. ``file-1``. These are used to create
       new instances of a class via the web interface.
 
+   detectors
+      There are two types of detectors that execute Python code in
+      response to changes to the database.
+
+      auditors
+	are run before a permanent change is made to the database.
+	They validate that the change is allowed. For example is
+	the current user allowed to change the status field.
+
+      reactors
+	are run after a change has been committed to the
+	database. They are used to perform actions like sending
+	notification messages, updating other tickets etc.
+
    html directory
       there is a directory called **html** in tracker homes. This
       contains html files (called templates) that are processed by the
@@ -65,6 +79,22 @@ Roundup Glossary
       tracker. Contained in the file ``schema.py``. The permissions
       for the schema items are usually defined in the same file.
 
+   template
+
+      this term has two meanings depending on context.
+
+      It refers to files that are processed by a templating engine to
+      produce output suitable for machine or human consumption. For
+      example a template could produce a html page that includes the
+      name of the user.
+
+      It also can mean a **Tracker template**. This is a set of files
+      used to install a new tracker. Tracker templates define a
+      tracker with a particular look and feel, :term:`schema`,
+      permissions model, and :term:`detectors`. Roundu ships with five
+      templates and people on the net `have produced other templates`_
+
+
    tracker
       the schema and hyperdb that forms one issue tracker
 
@@ -77,5 +107,6 @@ Roundup Glossary
 
 Back to `Table of Contents`_
 
+.. _`have produced other templates`: https://wiki.roundup-tracker.org/TrackerTemplates
 .. _`Table of Contents`: ../docs.html